The Applicant claims foreign priority benefits for this application under 35 U.S.C. xc2xa7 119 of DE 102 42 253.2 filed on Sep. 12, 2002.
1. Field of the Invention
The present invention relates to an electric switch unit such as a steering column switch assembly having a rotary-push switch group placed at the free end of a switch lever, the switch unit including at least one rotary switch as well as a push switch that can be actuated by means of a pushing movement relative to the switch lever, whereby the one or more rotary switches and the push switch each have movable electrical contact elements that can be actuated by means of a respective actuating element and are supported on a fixed strip conductor structure that is held by a support and have corresponding fixed electrical contact surfaces on the fixed strip conductor structure.
2. Background Art
Electric switch units of this type are used in the automobile industry as steering column switches, for example. The switch lever on the free end of which the rotary-push switch group is placed is itself supported in pivoting fashion. The switch lever can be the vehicle""s turn signal switch, for example.
An electric switch unit with the features mentioned above is known from DE 197 23 482 C1. The rotary-push switch group of this switch unit includes a rotary switch, the actuating element of which represents a cap that forms the free end of the rotary-push switch group. Various switch positions can be obtained by rotating the actuating cap around its longitudinal axis. Additional switching functions can be obtained by exposing the rotary-push switch group to a pushing force directed towards the switching lever, whereby the push switch arrangement is designed as a pushbutton switch.
The rotary switch and the push switch of this rotary-push switch group each have movable electrical contact elements. Each movable electrical contact element can be actuated by means of an actuating element and are supported on a fixed strip conductor structure. The required fixed electrical contact surfaces are part of this fixed strip conductor structure. Each of the movable electrical contact elements is held in a slider that is moved by the movement of the associated actuating element. The direction of movement of the slider lies in the longitudinal direction of the rotary-push switch group.
In order that the slider, which is provided for the rotary switch and bears the movable electrical contact elements, can be moved in the longitudinal direction in response to a rotary movement of the actuating cap on the end, the rotary movement of the actuating element must be converted into a translational movement for driving the slider. Provided for this purpose is a function element having a guide track in which a guide pin of the slider bearing the movable electrical contact elements engages. The function element is push-decoupled relative to the actuating cap of the rotary switch, but is positively engaged with this cap in terms of rotary torque.
The strip conductor structure surrounding the fixed electrical contact surfaces is a rigid circuit board that is contacted by means of a connection cable set. The circuit board is held by a support that is fastened in non-rotating and non-sliding fashion on the free end of the lever arm.
The sliders of the two switches of this rotary-push switch group bearing the movable electrical contact elements are arranged one after the other in the axial direction. This is done primarily against the background that with a configuration of a different design, the diameter of the rotary-push switch group would become too large. The axial length of the rotary-push switch group is thus co-determined by the number of sliders bearing the movable electrical contact elements.
At a higher functional density than that described in DE 197 23 482 C1, for example, in a configuration of a rotary-push switch group with two or more rotary switches, the axial extent of the switch unit described in the cited document would lengthen. Thus, an increase in the limits of the functional density of this previously known switch-unit is demonstrated, particularly with regard to a larger number of rotary switches, if a simultaneous increase in the diameter of the rotary-push switch group is not desirable.
Known from DE 195 38 767 A1 is another electric switch unit, which is designed as a steering column switch. Unlike the object of DE 197 23 482 C1, however, this switch unit includes only one push switch and no rotary-push switch group. In principle, the push switch of this document is constructed in a manner similar to that of the previously cited document. Unlike the previously described switch unit, the fixed electrical contact elements are part of a flexible conductive foil that is supported, in the region of the contacting carried out by the movable electrical contact elements, by a support so that adequate counter-support is provided for the movable electrical contact elements. The direction of movement of the movable electrical contact elements relative to the fixed conductive foil also lies in the longitudinal direction of the switch unit.
Starting from DE 197 23 482 C1, the present invention is based on the task of further developing an electric switch unit with a rotary-push switch group of the type mentioned above in such a way that in order to increase the functional density, the rotary-push switch group can not only be equipped with a greater number of rotary switches without having to extend the axial length of the rotary-push switch group excessively relative to the previously known configuration, but rather that the rotary switch or switches that are used can be made with fewer parts.
According to the present invention, this task is solved through the fact that the plane of the fixed electrical contact elements of the one or more rotary switches lies transverse to the longitudinal (i.e., axial) direction of the rotary-push switch group, and that assigned to each rotary switch is a slider, which is positively engaged to an actuating element of the corresponding rotary switch in terms of rotational torque but is push-decoupled relative to a pushing movement of the actuating element with the movable electrical contact elements.
Unlike the prior art, in this switch unit the plane of the fixed electrical contact elements lies transverse to the longitudinal direction of the rotary-push switch group, and thus transverse to the axis of rotation of the actuating element of the one or more rotary switches. The movable electrical contact elements of the rotary switch are thus guided along a movement path that is concentric with the axis of rotation of the actuating element. For this reason, the axial structural space that is required is reduced relative to previously known switch units; specifically, a plurality, for example, two rotary switches can be placed axially one behind the other without having to excessively increase the overall length of the rotary-push switch group.
An additional advantage of this configuration is the fact that the movable electrical contact elements of the rotary switch or switches can be moved by the actuating elements with no translational movement. A slider that is rotary torque-connected in positive fashion to its particular actuating element but is push-decoupled relative to a movement of the actuating element is assigned for that purpose to the movable electrical contact elements of each of the rotary switches.
For example, the slider can be a plastic body on which the movable electrical contact elements are placed. In principle, the movable electrical contact elements can be configured in such a way that they also have the function of the described slider. Such a kinematic connection, positively engaged in terms of torque but push-decoupled, with an actuating element can be realized, for example, with a fork, which is assigned to the slider and lies parallel to the axis of rotation, and in which a driving pin, designed as a pin or a web for example, of the actuating element engages. The driving pin can move freely in the axial direction within the fork, at least over the range of motion of the push switch, so that a push movement of the actuating element is not transmitted to the slider.
The strip conductor structure with fixed electrical contact surfaces for each rotary switch is advantageously a section of a flexible foil conductor, by means of which all of the required electrical wiring is realized, including the connections. The flexible properties of such a foil conductor are fully utilized for the placing of the plane of the fixed electrical contact surfaces, which plane lies transverse to the longitudinal direction of the rotary-push switch group, because it can easily be brought into the desired spatial arrangement of the fixed contact surfaces by means of folding or bending without it being necessary for several independent, separate strip conductor structures to be specially brought into electrical contact with each other for this purpose.
Such a flexible strip conductor is supported in the region of the fixed electrical contact surfaces by the support, which provides in each of these regions a contact frame or something similar. In a realization of, for example, two rotary switches, a contact frame that is placed transverse to the longitudinal direction of the rotary-push switch group can be used in order to place a section of such a foil conductor with fixed electrical contact surfaces on each of its end surfaces facing in the axial direction, and to fasten them to it.
Particularly when a flexible foil conductor is used, the push-switch arrangement can be placed in the region of the end of the rotary-push switch group that faces the end of the switch lever with no additional effort, so that additional space is available in the outer region of the rotary-push switch group for the placement of rotary switches.
In an advantageous configuration, the slider assigned to one rotary switch is mounted axially on the support. To install the slider on the support, the support advantageously has a radial installation or insertion opening that runs into an axial bearing opening. The slider can thus be placed radially on the provided axle of the support. The bearing opening of the slider is advantageously configured in such a way that the slider is held locked on the bearing axle of the support.
When two rotary switches are placed axially one axially behind the other inside such a rotary-push switch group, it is advantageous to separate them from each other by means of a torque-decoupled intermediate ring. Such an intermediate ring advantageously has spring means that act in the push direction (towards the switch lever) so that the two adjacent actuating rings of the rotary switches are play-free.